1. Field of the Invention
The present invention relates to a push switch.
2. Description of the Related Art
Conventional push switches include, for example, switch operation devices that are installed in vehicles and operated by pressing from the exterior (Japanese Patent Laid-Open Publication No. 2008-10360). As shown in FIG. 10(a) and FIG. 10(b), this push switch comprises a switch case 101, made from hard resin, a switch button 102, made from soft resin, and a main switch unit 107.
This switch case 101 is formed as a rectilinear box having a space at the interior for receiving the switch button 102. The main switch unit 107 is assembled at the interior of the switch button 102, and a thermosetting resin 111 is applied at the interior of the switch case 101. This thermosetting resin 111 solidly fixes the main switch unit 107 in place in the switch case 101 and the switch button 102, and allows for waterproofing of the main switch unit 107.
However, in methods where the resin is applied (injected) into the switch case, it is difficult to fill the interior of the switch case without gaps, and thus gaps may occur between the resin and the inner side of the switch case. In this event, if drops of water adhere to the bottom of the switch case, there is a risk that these drops of water will infiltrate the main switch unit, which reduces the waterproofness of the push switch.
Furthermore, the work of applying the thermosetting resin requires much time and skill, which greatly reduces productivity.